Do I have some incorrect options here? I would've thought these would go away, but they were the same in 1.31. I can't find others reporting the same warnings. With this at the beginning of my source: #include <boost/date_time/gregorian/gregorian.hpp> #include <boost/date_time/posix_time/posix_time.hpp> #include <boost/date_time/date_generators.hpp> ...on VC71, boost 1.32 with all defaults during build of boost, with these compiler options: /Od /I "..\..\..\Vendor\Boost\1_32_0\include\boost-1_32" /I "..\..\..\Vendor\ace\5_4\dev" /I "..\..\..\Vendor\Apache\Xerces_C\2_6_0\dev" /I "..\\" /D "WIN32" /D "_DEBUG" /D "_LIB" /D "_MBCS" /Gm /EHsc /RTC1 /MDd /GS /Fo"Debug/" /Fd"c:\my_lib\/lib/my_libD.pdb" /W3 /c /Zi /TP .\MyFile.cpp ...and getting these warnings: ..\..\..\vendor\boost\1_32_0\include\boost-1_32\boost\date_time\time_system_coun ted.hpp(57) : warning C4244: 'initializing' : conversion from 'boost::date_time::counted_time_rep<config>::int_type' to 'boost::date_time::gregorian_calendar_base<ymd_type_,date_int_type_>::date_int_t ype', possible loss of data with [ config=boost::posix_time::millisec_posix_time_system_config ] and [ ymd_type_=boost::gregorian::greg_year_month_day, date_int_type_=boost::date_time::int_adapter<unsigned long>::int_type ] ..\..\..\vendor\boost\1_32_0\include\boost-1_32\boost\date_time\time_system_coun ted.hpp( 52) : while compiling class-template member function 'boost::date_time::counted_time_rep<config>::date_type boost::date_time::counted_time_rep<config>::date(void) const' with [ config=boost::posix_time::millisec_posix_time_system_config ] ..\..\..\vendor\boost\1_32_0\include\boost-1_32\boost\date_time\time_system_coun ted.hpp( 111) : see reference to class template instantiation 'boost::date_time::counted_time_rep<config>' being compiled with [ config=boost::posix_time::millisec_posix_time_system_config ] ..\..\..\vendor\boost\1_32_0\include\boost-1_32\boost\date_time\time.hpp(52) : see reference to class template instantiation 'boost::date_time::counted_time_system<time_rep>' being compiled with [ time_rep=boost::posix_time::int64_time_rep ] ..\..\..\vendor\boost\1_32_0\include\boost-1_32\boost\date_time\posix_time\ptime .hpp(32) : see reference to class template instantiation 'boost::date_time::base_time<T,time_system>' being compiled with [ T=boost::posix_time::ptime, time_system=boost::posix_time::posix_time_system ] ..\..\..\vendor\boost\1_32_0\include\boost-1_32\boost\date_time\date_parsing.hpp (211) : warning C4244: 'argument' : conversion from 'std::allocator<_Ty>::value_type' to 'char', possible loss of data with [ _Ty=wchar_t ] ..\..\..\vendor\boost\1_32_0\include\boost-1_32\boost\date_time\date_parsing.hpp (253) : see reference to function template instantiation 'date_type boost::date_time::from_stream_type<date_type,std::basic_string<_Elem,_Traits,_Ax
::iterator>( iterator_type &,iterator_type &,wchar_t)' being compiled with [ date_type=boost::gregorian::date, _Elem=wchar_t, _Traits=std::char_traits<wchar_t>, _Ax=std::allocator<wchar_t>,
iterator_type=std::basic_string<wchar_t,std::char_traits<wchar_t>,std::allocator < wchar_t>>::iterator ] ..\..\..\vendor\boost\1_32_0\include\boost-1_32\boost\date_time\gregorian\parser s.hpp(78) : see reference to function template instantiation 'boost::date_time::period<point_rep,duration_rep> boost::date_time::from_simple_string_type<boost::gregorian::date,wchar_t>(const std::basic_string<_Elem,_Traits,_Ax> &)' being compiled with [ point_rep=boost::gregorian::date, duration_rep=boost::gregorian::date_duration, _Elem=wchar_t, _Traits=std::char_traits<wchar_t>, _Ax=std::allocator<wchar_t> ]